I recently bought a used bike and am looking to fix a couple things that are wrong with it.

One thing is that in some places -- especially the chainstay and on the underside of where the bottom bracket goes [from the chain slipping off the smallest front gear, I think] -- the paint is worn down to the aluminum frame.

I want to at least prevent the paint from peeling further, dirt getting in, or huge gashes being made to the frame, since it's a pretty nice frame I think.

Sand it down where needed, mask it off and throw down a couple of coats of auto paint that matches, then sray some clear coat over that. Hell, use something intentionally mismatched and tell people it's custom and all the cool kids are doing it.

I recently bought a used bike and am looking to fix a couple things that are wrong with it.

One thing is that in some places -- especially the chainstay and on the underside of where the bottom bracket goes [from the chain slipping off the smallest front gear, I think] -- the paint is worn down to the aluminum frame.

I want to at least prevent the paint from peeling further, dirt getting in, or huge gashes being made to the frame, since it's a pretty nice frame I think.